1. Field of the Invention
The present invention relates to a magazine for containing a plurality of electronic media cartridges and more particularly to a magazine which will indicate the processing status of the cartridges contained therein.
2. Discussion of the Related Art
When large volumes of data are to be processed in a computer system, it is convenient to employ magazines which accommodate numerous electronic media cartridges, such as magnetic tape cartridges. These magazines will typically contain ten or 12 cartridges in a vertically stacked array. The cartridges can be loaded in the magazine manually or by a remotely operated cartridge picker. Once the cartridges are loaded in the magazine, they are ready for processing, such as during a read operation by a tape drive. In order to perform this operation, a cartridge picker will remove the cartridge from the magazine, transport it to the tape drive and then return the cartridge to the magazine after processing.
The advantage of a magazine is that it confines the cartridges to a compact area where they can be organized in some logical fashion. By having the cartridges vertically stacked they are efficiently positioned for transport operations by the cartridge picker. Because the magazine supports cartridges on individual shelves, the cartridges support only their own weight, and each cartridge can be easily slid along its shelf for the processing operation. Typically the cartridges are placed on shelves from an open side of the magazine and then processed from an opposite open side of the magazine.
In the past, it has been very difficult to ascertain whether or not a particular cartridge in a magazine has been processed by the cartridge picker and cartridge drive. When the magazine is viewed by an operator there is no indication whether or not any processing has occurred. It can be envisioned that many different types of electronic indicators could be devised to provide a visible display. However, this requires a power source and adds undue complexity to the magazine. Therefore, it is desirable that a mechanical indicator be provided so that visual inspection of the magazine will indicate whether or not any one of the cartridges has been processed.